Blanking die and method of making the same



July 31, 1962 F. R. MOE

BLANKING DIE AND METHOD OF MAKING THE SAME Filed July 10, 1957 2Sheets-Sheet l INVENTOR.

lib. Lu m FRANKRMOE BY M, M

July 31, 1962 F. R. MOE 3,046,815

BLANKING DIE AND METHOD OFMAKING THE SAME Filed July 10, 1957 2Sheets-Sheet 2 /-29 T g-. 6 1% v 1 f;

INVENTOR.

QMtornegs niteci t York Filed Euly 10, 1%5'7, Ser. No. 679,910 3 Claims.(Ci. 76-407) This invention relates to blanking die assemblies adaptedto successively punch blanks from sheet material and particularlyrelates to a method of making the die assembly.

It has been known to employ a die assembly having a hardened rule with acutting edge which moves relative to and cooperates with a punch memberto punch out blanks from sheet metal or the like. The use of a separatehardened rule permits the use of relatively soft materials for the othercomponents which may be easily formed.

In the above construction, me edges of the punch member preferably lieimmediately within the perimeter of the rule such that when the membersare telescoped into cutting relation, the edge surface. of the punchmember is flush with the inner face of the rule. This action providesexcellent blanks having clean and even edges. However, very accuratecorrespondence between the edge surface of the punch member and the ruleis required.

It is presently known to form the rule into the desired configuration bycutting the configuration into a platelike member. The width of the cutis made to correspond substantially to the thickness of the rule suchthat the rule may be wedged within the cut. This requires very accuratecutting and subsequent machining of a punch member.

In accordance with the present invention, a plate-like die member isprovided with an opening by removing a centerpiece having the generalconfiguration of the blanks to be made, but which is somewhat larger allaround than the final blank. The cut out centerpiece, which issubsequently employed as a punch pad, is assembled with a master patternof the blank and with a punch member. The edges are then machined to theshape of the master pattern to simultaneously form precisely the sameconfiguration of the punch and the punch pad. The cutting 4 rule is thensecured to the perimeter of the punch pad and disposed within theopening formed in the die member. A viscous material which is capable ofsetting into a very hard mass is disposed within the space between eopening in the die member and the cutting rule. When this materialhardens, it clamps the rule and connected punch pad within the opening.The die member and the punch member are then asssembled with a suitableoperating mechanism with the rule accurately aligned with the punchmember. Suitable stripping members, knockouts and the like, are normallyprovided to assist in ejecting the stamped and excess material frombetween the die member and the punch member.

The viscous material is preferably a suitable plastic which willadhesively bond to the die member and the cutting rule to adhesivelysupport the members together.

* "ice mode presently contemplated by the inventor for carrying out theinvention.

In the drawings:

FIGURE 1 is a cross sectional view of a punch and die assembly;

FIG. 2 is a plan view of the punch assembly taken on line 22 of FIG. 1;

FIG. 3 is an inverted plan view of the die assembly taken on line 3-3 ofFIG. 1;

FIG. 4 is a perspective view of a completed stamping for purposes ofillustration;

FIG. 5 is a plan view of a die ring in the first step in the forming ofthe die and punch assemblies;

FIG. 6 is a cross sectional view of a master pattern of the stamping ofFIG. 4 assembled with various components which are to be machined to theconfiguration of the master pattern;

FIG. 7 is a cross sectional view of a die ring and a cutting ruleshowing the method of assembly; and

FIG. 8 is a fragmentary view in section of the punch and die assembly ofFIG. 1 during a punching operation.

Referring to the drawings and particularly FIG. 1, blanking apparatus isshown comprising a lower punch assembly 1 secured to a punch platesupport 2 and an upper die assembly 3 secured to a movable shoe oradapter plate 4 of a hardened material which in turn is secured to a ramor the like, not shown. The punch assembly 1 and die assembly 3 areshown in a relatively separated state with a metal sheet 4 disposedtherebetween. A shear blade 6 in the upper die assembly 3 is adapted tocooperate with a punch 7 in the punch assembly 1 to cut out a metalblank 8 when the die assembly 3 is depressed or lowered.

The metal stamping 8 is shown perspectively in FIG. 4 and is shown as agenerally rectangular member having relative rounded corners. Thisrelatively simple configuration is shown for purposes of clarity ofillustration only and the stamping may have a much more complicatedconfiguration.

Referring particularly to FIGS. 1 and 2, the lower punch assembly 1includes a base plate 9 which is substantially larger than the punch 7which it carries. The base plate 9 is removably secured to the punchplate support 2 by a plurality of suitably spaced bolts 10. The punch 7is secured to a filler plate 11 by a plurality of spaced bolts 12 andthe filler plate is machined to the same outline as the punch 7. Theconnected punch 7 and filler plate 11 are secured to or rest upon thebase plate 9 with a pair of dowels 13 accurately positioning them on thebase plate. A pair of punch holes 14 are provided in the punch 7 toallow formation of a pair of openings 15 in the blank 8. The holes 14are aligned with suitable enlarged openings 16 in the tiller plate 11and the base pltae 9 to allow discharge of metal through Openings 17 insupport 2 when forming openings 15 in the metal blank 8.

A stripper 18 encircles the punch 7 and is provided with fourcircumferentially spaced openings 19 which accommodate the heads 20 offour upstanding bearing bolts 21, which thread into the base plate 9'. Abearing surface 22'. is provided by the bolts between the plate 9 andthe stripper 18. A cup-shaped member 23 has its upper edge secured tothe undersurface of the stripper 18 at each opening 19 and is providedwith openings in its lower surface corresponding to the diameter of thebearing surface 22 on bolts 21 to slidably support the stripper 1%. Aresilient pad 24 is coextensively disposed beneath the stripper 18 withsuitable openings for the bolts 21. The pad 24- resiliently urges thestripper 18 upwardly to dispose the upper surface of the stripper 18 andthe punch 7 in the same horizontal plane with the pad in an unstressedstate.

Patented July 31, 1962 area of the same sheet.

The resilient pad 24 may or the like, or any other suitable materialwhich has the desired degree of resiliency and is not adversely afiectedby surrounding foreign mattter. v When the die assembly'3 drops'to cutout the punch 8, the stripper 18 is forced downwardly. When the dieas-.sembly 3 retracts, the resilient member24 forcesthe stripper 18 back toits original position and strips the marginal portionof sheet 5 fromthe'punch 7 (to allow removal thereof and insertion of a new sheet or anew As the pad 24 is substantially coextensive with :the'stripper 18, aneven stripping pressure is applied to the adjoiningrnetal sheet 5.

Referring particularly to FIGS. l and 3, the illustrated I die assembly3 comprises a supporting die ring 25 which is secured to the adapterplate4'by a plurality of' spaced be formed of neoprene rubber When thedie assembly 3 is depressed to cut out the stampbolts 26. Alignmentdowels 27 are provided to initially v position the die ring 25 and theadapter plate '4. An opening 28 in the die ring 25 roughly correspondsto V the outline of the'punch 7 but is' somewhat larger. The

shear blade 6 is clamped within the opening 28 in pre- ,cise alignmentwith the punch 7 by a punch pad 29 and a plastic and sand filler 30disposed between the edge 29 is formed precisely to the same outline aspunch 7 "and, therefore, with the punch pad 29 :and the punch 7precisely aligned in superposed relation, the inner surface of the shearblade 6 lies in the same plane as the edge of the punch 7 When the blade6 is moved into .of the opening 28 and the shear blade 6. The punch padThe plastic andsand filler '30 which is disposed between the blade '6and the adjacent surface of the ope ing 28 serves to clamp the blade, 6:and pad 29 to the die ring 25 to form a unitary die assembly. The faceof the uni- 'tary die assembly immediately adjoining the adapter plate'4 is machined to'prevent vibration of the parts.

The plastic is preferably of a variety to eifect a bond to the adjacentsurface of the blade 6 and the die ring 25 to securelysupport the blade6. The use of a sand and plastic mixture reduces the cost of the fillerover a pure plastic, although the latter is otherwise entirelysatisfactory.

A plurality of small screws 32 are shown securing the blade 6 totheipunch pad 29. The screws 32 are employed during the fabrication ofthe die assembly, as

more fully. described hereinafter.

The blade 6 is any suitable hardened steel or the like which can standthe wear of continuously punching out the blanks 8 from the sheet 5.Generally, a commercially available steel rule stock is entirelysatisfactory.

The blade 6 protrudes outwardly from the opening 28 in the die ring andis provided with a beveled knife edge 33 for severing blanks 8. A pairof punches 34 are disposed within suitableopenings in the punchpad 29,and are aligned the punch I holes 14 in punch 7 to form the openings 15in the completed blank 8. The punches each have an enlarged head 35disposed Within correspondingly shaped recesses in the surface of thepunch pad 29 immediately adjoining the adapter plate 4 to securely holdthe punches 34 in place. 7

To remove the force of the stripper 18 from the blade 6, a plurality ofpressure strips 36 encircle the blade 6 and are welded to the undersideof the die ring 25 in outwardly spaced relation to the blade 6. Thestrips 36 have the same vertical depth as the extent of the protrusionof theblade 6 from the die ring 25 such that the lower surface ofpressure strips 36 and the end of knife edge '33 of blade 6 are in thesame horizontal plane.

stripper 18 through the interposed sheet 5 and remove the load from theblade 6.

A knockout plate 37 is operatively secured within the a confines of theblade 6 to prevent the completed blank 8 from rising upwardly with theblade 6. The punch pad V 29 is somewhat thinner than the die ring 25 toform a space within the blade 6to accommodate the plate. The

shape of plate 37 generally corresponds to the configuration of blank 8and the outer edge of plate 37 is disposed in spaced relation to theblade 6. The plate 37 is secured in place by a pair of knockout pins 38,which extend upwardly throughsuitable aligned openings 39 and 40 in thepunch pad 29' and the adapter plate 4 respeotively. The upper ends ofthe pins 38 are secured to a portion of the press assembly, not shown.Coil springs 41 encircle the pins 38 between the punch pad 29 and theknockout plate 37 and bias the pins 38 and attached knockout plate 37outwardly into engagement with the sheet 5 or blank 8 which lies betweenthe knockout plate 37 and the punch 7. Acoun-tersunk re-' cess 42 isprovided in each of the openings 40 to re ceive a crosspin 43 whichextends through the pin 38 and is adapted to engage punch pad 2?. Thecrosspins 43 support the pins 38 in the retracted die assembly positionshown in 'FIG. 1. V j

The adapter plate 4 is provided with a plurality of the knockout pinopenings 48 each having a countersunk recess 42 such that a variety ofdilferent die forms can be selectively secured to a single adapterplate. The openings 40 which are not being used are each sealedby asmall screw 44 which is adapted to thread intogthe correspondinglytheraded openings 48,. The screws 44 are hardened and have a fiat head45 which is formed to precisely the same dimensions as the countersunkrecesses 42 and maintain a continuous hardened backing surface for therule 6 and the punches '34. For example the screws 44 can be assembliedwith the adapter plate '4 and simultaneously machined to a smoothcontinuous surface.

When the die assembly 3 is depressed to cut out the stamping 8, as shownin FIG. 8, the knockout plate 37 is brought into engagement with theupper surface of the blank 8. As the die assembly 3 continues to lowerand cut out the blanks 8,-the springs 41 are compressed.

When the die assembly3 is retracted topermit removal of the blank 8, thesprings 41 expand to maintain the stamping 8 against the upper surfaceof punch 7. At the uppermost position of the die assembly 3, theknockout plate 37 is lifted upwardly into spaced relation with thestamping 8 and allows removal thereof and insertion bf.

new material; V 7

Suitable openings 47 are provided in the knockout plate 37 to permit thepunches 34 to pass therethron'gh and into the punch openings 16. Anopening 48 is also provided to accommodate the head of the take'up bolt31. In accordance with the presentyinvention, the punch 5' assembly land the die assembly are made in the following manner.

Referring to FIG. 5 the die ring 25 is formed from a plate like memberby disposing a master pattern '58 upon the member. The master pattern 58corresponds to the configuration of the desired blank 8 and is traced.onto the unformed diering 25. The opening 28 is then formed in the diering 25 in any suitable manner such as by burning out the centralportion alongan outline 49 which is in slightly spaced relation to theoutline formed by the master pattern 58. The spacing of outline 49 issomewhat the punch 7 which at this point are also uniormed. The masterpattern 58 is secured in stacked relation therewith and the assembledstack held together by suitable dowels 50' disposed in suitable alignedopenings which may be located to serve as cooperating openings forpunches 34 or the like. The edges of the pad 29, filler plate 11 andpunch 7 are then simultaneously machined to the configuration of themaster pattern 58 to provide a final assembly as shown in FIG. 6. Thepunch 7, punch pad 29 and filler plate 11 may be of a relatively softmetal to allow easy machining of the edges. The punch 7 is thensubsequently hardened to provide a durable punch.

As appears in FIG. 1, the punch pad 29 is thinner than the die ring 25to accommodate the knockout plate 37 between the pad 29 and the punch 7.The punch pad 29 is machined to the required thickness either before orafter machining its edge.

The filler plate 11 and the punch 7 are then bolted together and thepunch holes 16 and 14, respectively, are formed therein by drilling orthe like. The required openings 39 for the knockout pins 38 and theopenings for punches 34 as well as for the takeup bolt 31 are drilled inthe punch pad 29.

The rule or shear blade 6 is then formed and secured to the machinededge of the punch pad 29 by the small screws 32. The die ring 25 and thepunch pad 29 are then disposed in an inverted position upon a machinedsupporting surface 51 with the punch pad 29 accurately centered withinthe opening 28 of the die ring 25 as shown in FIG. 7. The filler plate11 is disposed within the perimeter of the blade 6 immediately adjacentthe outer beveled blade end by a plurality of spacers 52 which aredisposed between the plate 11 and the punch pad 29. The plastic and sandfiller 38 is then poured into the opening 28 between the blade 6 and thedie ring 25 in an uncured condition. The machined supporting surface 51prevents the plastic from flowing beneath the surface of the die ring 25and the punch pad 29. The plastic subsequently hardens to clamp theassembly together and bond both the die ring 25 and the blade 6 in placeto securely connect the die ring and the punch pad.

The opening 28 need not be precisely formed because the location of theblade 6 is accurately provided for by the punch pad 29 and the plasticfills the space in the -die ring opening 28.

After the plastic 30 hardens, the filler plate 11 and spacers 52 areremoved. The die ring 25 and punches 34 and knockout plate 37 are thenassembled and attached to the adapter plate 4, as shown in FIG. 1.

The filler plate 11 and punch 7 are secured together by the bolts 12 andattached to the base plate 9, as shown in FIG. 1. The stripper 18 issecured to the base plate to complete the lower punch assembly.

The punch pad 29 and the punch 7 are precisely aligned and due to thesimultaneous machining of their edges, as previously described,'theshear blade 6 moves downwardly into flush relationship with the edge ofthe punch 7 to form a clean and perfect stamping having a very smoothedge.

It the blade 6 should become Worn to an extent requiring replacement,the plastic filler 30 is easily removed and a new rule connected orassembled therewith.

The present invention provides a blanking device for forming precise andaccurate blanks. The punching device is easily and rapidly made andemploys ready available materials which may be conveniently obtained andformed.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following 'claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

I claim: 8

1. A method of making a blank forming device, which comprises burningout a centerpiece having an enlarged outline of the blank to be formedfrom a die block of easily machined metal to form a die ring, stackingthe centerpiece and a punch with a master pattern, machining the edgesof the centerpiece and the punch together to the outline of the masterpattern, hardening the machined punch, reducing the thickness of thecenterpiece, securing a cutting rule having a depth slightly greaterthan the depth of the die ring and centerpiece to the periphery of thecenterpiece with the rule extending from only one surface of thecenterpiece, reassembling the centerpiece centrally within the openingof the die block with the lower surfaces of the die ring and thecenterpiece in the same horizontal plane, filling the space between thewall of the opening and the rule with a miX- ture of uncured plastic andsand, curing the plastic to a hardened mass, and operatively mountingsaid die ring and punch in opposed relation with said punch and saidcenterpiece in exact superposed relation.

2. A method of making a blank forming device, which comprises burningout a centerpiece having an enlarged outline of the blank to be formedfrom a die block of easily machined metal reducing the thickness of thecenterpiece, stacking the centerpiece and a punch with a master pattern,machining the edges of the centerpiece and the punch together to theoutline of the master pattern, hardening the machined punch, securing acutting rule having a depth slightly greater than the depth of the diering to the periphery of the centerpiece With the rule extending fromonly one surface of the centerpiece, reassembling the centerpiececentrally within the opening of the die block with the lower surfaces ofthe die ring and the centerpiece in the same horizontal plane, fillingthe space between the wall of he opening and the rule with a mixture ofuncured plastic and sand, curing the plastic to a hardened mass, andoperatively mounting said die ring and punch in opposed relation withsaid punch and said centerpiece in exact superposed relation.

3. A method of forming a metallic die assembly including a hardenedpunch assembly and a die assembly to form metallic blanks, whichcomprises the steps of removing a centerpiece from a plate member of arelative- 1y soft metal to define a centerpiece member and an opening inthe plate member larger than the blank to be formed, assembling saidcenterpiece member and a metallic punch of soft metal larger than theblank to be formed in stacked relation, machining the edges of thecenterpiece member and the punch to the precise outline of the blank tobe formed, reducing the thickness of the centerpiece member, securing ahardened rule to the perimeter of the centerpiece member with the ruleprojecting perpendicularly from the plane of the centerpiece member,said rule having a thickness less than the spacing between the edge ofthe opening in the plate member and centerpiece member, and mounting thecenterpiece member and the attached rule within the opening in the platemember.

References Cited in'the file of this patent UNITED STATES PATENTS922,926 Lynch May 25, 1909 1,095,116 Kaven Apr. 28, 1914 1,095,117 KavenApr. 28, 1914 1,843,753 De Witt et a1. Feb. 2, 1932 2,212,886 RulandAug. 27, 1940 2,433,058 Mesaros Dec. 23, 1947 2,643,715 McClellan June30, 1953 2,765,034 WilShaw Oct. 2, 1956 2,791,134 Bien May 7, 19572,821,871 Sarno Feb. 4, 1958 2,853,134 Deubel Sept. 23, 1958 2,885,913Lescallette May 12, 1959 FOREIGN PATENTS 295,467 Great Britain Aug. 16,1928

